Projet de thèse de doctorat : Contribution au développement d'approches de modélisation et de techniques de caractérisation et de contrôle des supraconducteurs à haute température critique

Doctoral thesis project: Contribution to the development of modeling approaches and techniques for the characterization and control of high-temperature superconductors High-temperature superconducting (HTS) materials have a high potential for application in electrical power systems, enabling significant increases in power mass densities beyond a certain power threshold, while increasing the energy efficiency of the systems [1-2]. However, in addition to the effect of temperature, the electromagnetic performance of HTS is highly dependent on the applied magnetic field, which is nevertheless the primary driver of electromagnetic and electromechanical energy conversion. Therefore, prior characterization of HTS under various electromagnetic conditions is necessary before their integration into power systems. HTS elements, particularly second-generation ribbons which are multilayer assemblies, can also exhibit structural defects that may compromise the reliability of the systems in which they are integrated [3-4]. It is thus necessary to develop reliable testing techniques that can adapt to the very thin structures of these ribbons, where the layer thicknesses are on the order of micrometers. In previous works [5-8], we invested in developing multiphysics modeling approaches and original control and characterization techniques of HTS, where the scientific and technical challenges are linked to the heterogeneous, multi-scale structures of these materials, as well as their strongly nonlinear electromagnetic behavior. This project is a continuation of this work, with the following objectives: • Improving the numerical performance of the developed models, which are primarily based on volume integral methods: - Considering the proximity of ferromagnetic materials with their nonlinear magnetic properties, and improving the numerical solution schemes that consider both the electrical nonlinearity of superconductors and the magnetic nonlinearity of ferromagnetic materials. - Multiphysics coupling of models - Extension of the models to three-dimensional structures, requiring model size reduction • Development of strategies for characterizing the electromagnetic properties of HTS under different electromagnetic environments, as well as control strategies for the detection and characterization of structural defects in HTS tapes using a nondestructive testing and evaluation approach. This requires a combination of numerical and experimental approaches. The technological platforms available at the Laboratory (GREEN) enable the development of experimental manipulations for validating the developed models and characterization approaches. Key words: High temperature superconductors, modeling, characterization, nondestructive testing, inductive thermography Candidates should hold a Master's degree (Bac +5) or equivalent in electrical engineering, with in-depth knowledge of low-frequency electromagnetism and with an interest in scientific research. Experience in numerical modeling in electromagnetism would be an asset. Furthermore, certain qualities are essential for conducting research: scientific curiosity, autonomy and teamwork, humility, rigor, and commitment. Starting : Octobre 2026. Funding: Doctoral contract with the University of Lorraine. Workplace : Université de Lorraine - Groupe de Recherche en Energie Electrique de Nancy (GREEN) – FST, Nancy. Contacts: Hocine Menana (hocine.menana@univ-lorraine.fr ) / Jean Lévêque (jean.leveque@univ-lorraine.fr )